Time-resolved x-ray spectroscopy of deeply buried tracer layers as a density and temperature diagnostic for the fast ignitor
The fast igniter concept for inertial confinement fusion relies on the generation of hot electrons, produced by a short-pulse ultra-high intensity laser, which propagate through high-density plasma to deposit their energy in the compressed fuel core and heat it to ignition. In preliminary experiments designed to investigate deep heating of high density matter, we used a 20 joule, 0.5-30 ps laser to heat solid targets, and used emission spectroscopy to measure plasma temperatures and densities achieved at large depths (2-20 microns) away from the initial target surface. The targets consisted of an Al tracer layer buried within a massive CH slab H-like and He-like line emission was then used to diagnose plasma conditions. We observe spectra from tracer layers buried up to 20 microns deep, measure emission durations of up to 200 ps, measure plasma temperatures up to T{sub c} = 650 eV, and measure electron densities near 10{sup 23} cm{sup -3}. Analysis is in progress, but the data appear to be in reasonable agreement with simulations when space-charge induced inhibition is included in hot-electron transport.
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- W-7405-Eng-48
- OSTI ID:
- 16371
- Report Number(s):
- UCRL-JC-126309; CONF-970407-; ON: DE98050989; TRN: US200302%%609
- Resource Relation:
- Conference: 13th International Conference on Laser Interactions and Related Plasma Phenomena, Monterey, CA (US), 05/13/1997--05/18/1997; Other Information: Supercedes report DE98050989; PBD: 26 Mar 97; PBD: 26 Mar 1997
- Country of Publication:
- United States
- Language:
- English
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